import os
import json
from http import HTTPStatus
from typing import Dict, Iterable, List

from flask import request, Response
from flask_restx import Resource

from mindsdb.interfaces.agents.agents_controller import AgentsController
from mindsdb.interfaces.storage import db
from mindsdb.api.http.utils import http_error
from mindsdb.api.http.namespaces.configs.projects import ns_conf
from mindsdb.api.executor.controllers.session_controller import SessionController
from mindsdb.metrics.metrics import api_endpoint_metrics
from mindsdb.utilities.log import getLogger
from mindsdb.utilities.exception import EntityExistsError, EntityNotExistsError


logger = getLogger(__name__)


AGENT_QUICK_RESPONSE = "I understand your request. I'm working on a detailed response for you."


def create_agent(project_name, name, agent):
    if name is None:
        return http_error(HTTPStatus.BAD_REQUEST, "Missing field", 'Missing "name" field for agent')

    model_name = agent.get("model_name")
    provider = agent.get("provider")
    skills = agent.get("skills", [])

    params = agent.get("params", {})
    if agent.get("data"):
        params["data"] = agent["data"]
    if agent.get("model"):
        params["model"] = agent["model"]
    if agent.get("prompt_template"):
        params["prompt_template"] = agent["prompt_template"]

    agents_controller = AgentsController()

    try:
        existing_agent = agents_controller.get_agent(name, project_name=project_name)
    except (ValueError, EntityNotExistsError):
        # Project must exist.
        return http_error(HTTPStatus.NOT_FOUND, "Project not found", f"Project with name {project_name} does not exist")
    if existing_agent is not None:
        return http_error(
            HTTPStatus.CONFLICT,
            "Agent already exists",
            f"Agent with name {name} already exists. Please choose a different one.",
        )

    try:
        created_agent = agents_controller.add_agent(
            name=name, project_name=project_name, model_name=model_name, skills=skills, provider=provider, params=params
        )
        return created_agent.as_dict(), HTTPStatus.CREATED
    except (ValueError, EntityExistsError):
        # Model or skill doesn't exist.
        return http_error(
            HTTPStatus.NOT_FOUND,
            "Resource not found",
            f'The model "{model_name}" or skills "{skills}" do not exist. Please ensure that the names are correct and try again.',
        )
    except NotImplementedError:
        # Free users trying to create agent.
        return http_error(
            HTTPStatus.UNAUTHORIZED,
            "Unavailable to free users",
            f'The model "{model_name}" or skills "{skills}" do not exist. Please ensure that the names are correct and try again.',
        )


@ns_conf.route("/<project_name>/agents")
class AgentsResource(Resource):
    @ns_conf.doc("list_agents")
    @api_endpoint_metrics("GET", "/agents")
    def get(self, project_name):
        """List all agents"""
        session = SessionController()
        try:
            all_agents = session.agents_controller.get_agents(project_name)
        except EntityNotExistsError:
            # Project needs to exist.
            return http_error(
                HTTPStatus.NOT_FOUND, "Project not found", f"Project with name {project_name} does not exist"
            )
        return [a.as_dict() for a in all_agents]

    @ns_conf.doc("create_agent")
    @api_endpoint_metrics("POST", "/agents")
    def post(self, project_name):
        """Create a agent"""

        # Check for required parameters.
        if "agent" not in request.json:
            return http_error(
                HTTPStatus.BAD_REQUEST, "Missing parameter", 'Must provide "agent" parameter in POST body'
            )

        agent = request.json["agent"]

        name = agent.get("name")
        return create_agent(project_name, name, agent)


@ns_conf.route("/<project_name>/agents/<agent_name>")
@ns_conf.param("project_name", "Name of the project")
@ns_conf.param("agent_name", "Name of the agent")
class AgentResource(Resource):
    @ns_conf.doc("get_agent")
    @api_endpoint_metrics("GET", "/agents/agent")
    def get(self, project_name, agent_name):
        """Gets an agent by name"""
        session = SessionController()
        try:
            existing_agent = session.agents_controller.get_agent(agent_name, project_name=project_name)
            if existing_agent is None:
                return http_error(
                    HTTPStatus.NOT_FOUND, "Agent not found", f"Agent with name {agent_name} does not exist"
                )
            return existing_agent.as_dict()
        except (ValueError, EntityNotExistsError):
            # Project needs to exist.
            return http_error(
                HTTPStatus.NOT_FOUND, "Project not found", f"Project with name {project_name} does not exist"
            )

    @ns_conf.doc("update_agent")
    @api_endpoint_metrics("PUT", "/agents/agent")
    def put(self, project_name, agent_name):
        """Updates an agent by name, creating one if it doesn't exist"""

        # Check for required parameters.
        if "agent" not in request.json:
            return http_error(
                HTTPStatus.BAD_REQUEST, "Missing parameter", 'Must provide "agent" parameter in POST body'
            )
        agents_controller = AgentsController()

        try:
            existing_agent_record = agents_controller.get_agent(agent_name, project_name=project_name)
        except (ValueError, EntityNotExistsError):
            # Project must exist.
            return http_error(
                HTTPStatus.NOT_FOUND, "Project not found", f"Project with name {project_name} does not exist"
            )
        if existing_agent_record is None:
            return http_error(
                HTTPStatus.BAD_REQUEST,
                "Creation is not allowed",
                "Creation of an agent using the PUT method is not allowed.",
            )

        agent = request.json["agent"]
        name = agent.get("name", None)

        # Agent must not exist with new name.
        if name is not None and name != agent_name:
            agent_with_new_name = agents_controller.get_agent(name, project_name=project_name)
            if agent_with_new_name is not None:
                return http_error(
                    HTTPStatus.CONFLICT,
                    "Agent already exists",
                    f"Agent with name {name} already exists. Please choose a different one.",
                )

        if existing_agent_record is None:
            # Create
            return create_agent(project_name, name, agent)

        # Update
        try:
            model_name = agent.get("model_name", None)
            skills_to_add = agent.get("skills_to_add", [])
            skills_to_remove = agent.get("skills_to_remove", [])
            skills_to_rewrite = agent.get("skills", [])
            provider = agent.get("provider")
            params = agent.get("params", {})
            if agent.get("data"):
                params["data"] = agent["data"]
            if agent.get("model"):
                params["model"] = agent["model"]
            if agent.get("prompt_template"):
                params["prompt_template"] = agent["prompt_template"]

            # Check if any of the skills to be added is of type 'retrieval'
            session = SessionController()
            skills_controller = session.skills_controller
            retrieval_skill_added = False
            if len(skills_to_add) > 0:
                skills_names = [x["name"] if isinstance(x, dict) else x for x in skills_to_add]
                retrieval_skill_added = any(
                    skills_controller.get_skill(skill_name).type == "retrieval"
                    for skill_name in skills_names
                    if skills_controller.get_skill(skill_name) is not None
                )
            elif len(skills_to_rewrite) > 0:
                retrieval_skill_added = any(
                    skills_controller.get_skill(skill_meta["name"]).type == "retrieval"
                    for skill_meta in skills_to_rewrite
                    if skills_controller.get_skill(skill_meta["name"]) is not None
                )

            if retrieval_skill_added and "mode" not in params:
                params["mode"] = "retrieval"

            updated_agent = agents_controller.update_agent(
                agent_name,
                project_name=project_name,
                name=name,
                model_name=model_name,
                skills_to_add=skills_to_add,
                skills_to_remove=skills_to_remove,
                skills_to_rewrite=skills_to_rewrite,
                provider=provider,
                params=params,
            )

            return updated_agent.as_dict()
        except EntityExistsError as e:
            return http_error(HTTPStatus.NOT_FOUND, "Resource should not exists", str(e))
        except EntityNotExistsError as e:
            # Agent or skill doesn't exist.
            return http_error(HTTPStatus.NOT_FOUND, "Resource not found", str(e))
        except ValueError as e:
            return http_error(HTTPStatus.BAD_REQUEST, "Wrong arguments", str(e))

    @ns_conf.doc("delete_agent")
    @api_endpoint_metrics("DELETE", "/agents/agent")
    def delete(self, project_name, agent_name):
        """Deletes a agent by name"""
        agents_controller = AgentsController()

        try:
            existing_agent = agents_controller.get_agent(agent_name, project_name=project_name)
            if existing_agent is None:
                return http_error(
                    HTTPStatus.NOT_FOUND, "Agent not found", f"Agent with name {agent_name} does not exist"
                )
        except (ValueError, EntityNotExistsError):
            # Project needs to exist.
            return http_error(
                HTTPStatus.NOT_FOUND, "Project not found", f"Project with name {project_name} does not exist"
            )

        agents_controller.delete_agent(agent_name, project_name=project_name)
        return "", HTTPStatus.NO_CONTENT


def _completion_event_generator(agent_name: str, messages: List[Dict], project_name: str) -> Iterable[str]:
    logger.info(f"Starting completion event generator for agent {agent_name}")

    def json_serialize(data):
        return f"data: {json.dumps(data)}\n\n"

    try:
        # Populate API key by default if not present.
        session = SessionController()
        existing_agent = session.agents_controller.get_agent(agent_name, project_name=project_name)
        if not existing_agent.params:
            existing_agent.params = {}
        existing_agent.params["openai_api_key"] = existing_agent.params.get(
            "openai_api_key", os.getenv("OPENAI_API_KEY")
        )
        # Have to commit/flush here so DB isn't locked while streaming.
        db.session.commit()

        if "mode" not in existing_agent.params and any(
            rel.skill.type == "retrieval" for rel in existing_agent.skills_relationships
        ):
            existing_agent.params["mode"] = "retrieval"

        completion_stream = session.agents_controller.get_completion(
            existing_agent, messages, project_name=project_name, tools=[], stream=True
        )

        for chunk in completion_stream:
            if isinstance(chunk, str) and chunk.startswith("data: "):
                # The chunk is already formatted correctly, yield it as is
                yield chunk
            elif isinstance(chunk, dict):
                if "error" in chunk:
                    # Handle error chunks
                    logger.error(f"Error in completion stream: {chunk['error']}")
                    yield json_serialize({"error": chunk["error"]})
                elif chunk.get("type") == "context":
                    # Handle context message
                    yield json_serialize({"type": "context", "content": chunk.get("content")})
                elif chunk.get("type") == "sql":
                    # Handle SQL query message
                    yield json_serialize({"type": "sql", "content": chunk.get("content")})
                else:
                    # Chunk should already be formatted by agent stream.
                    yield json_serialize(chunk)
            else:
                # For any other unexpected chunk types
                yield json_serialize({"output": str(chunk)})

            logger.debug(f"Streamed chunk: {str(chunk)[:100]}...")

        logger.info("Completion stream finished")

    except Exception:
        error_message = "Error in completion event generator"
        logger.exception(error_message)
        yield json_serialize({"error": error_message})

    finally:
        yield json_serialize({"type": "end"})


@ns_conf.route("/<project_name>/agents/<agent_name>/completions/stream")
@ns_conf.param("project_name", "Name of the project")
@ns_conf.param("agent_name", "Name of the agent")
class AgentCompletionsStream(Resource):
    @ns_conf.doc("agent_completions_stream")
    @api_endpoint_metrics("POST", "/agents/agent/completions/stream")
    def post(self, project_name, agent_name):
        # Extract messages from request (HTTP format only)
        if "messages" not in request.json:
            return http_error(
                HTTPStatus.BAD_REQUEST,
                "Missing parameter",
                'Must provide "messages" parameter in POST body',
            )

        messages = request.json["messages"]

        session = SessionController()
        try:
            existing_agent = session.agents_controller.get_agent(agent_name, project_name=project_name)
            if existing_agent is None:
                logger.warning(f"Agent {agent_name} not found in project {project_name}")
                return http_error(
                    HTTPStatus.NOT_FOUND, "Agent not found", f"Agent with name {agent_name} does not exist"
                )
        except ValueError as e:
            logger.warning(f"Project {project_name} not found: {e}")
            return http_error(
                HTTPStatus.NOT_FOUND, "Project not found", f"Project with name {project_name} does not exist"
            )

        try:
            gen = _completion_event_generator(agent_name, messages, project_name)
            logger.info(f"Starting streaming response for agent {agent_name}")
            return Response(gen, mimetype="text/event-stream")
        except Exception as e:
            logger.exception(f"Error during streaming for agent {agent_name}:")
            return http_error(
                HTTPStatus.INTERNAL_SERVER_ERROR, "Streaming error", f"An error occurred during streaming: {e}"
            )


@ns_conf.route("/<project_name>/agents/<agent_name>/completions")
@ns_conf.param("project_name", "Name of the project")
@ns_conf.param("agent_name", "Name of the agent")
class AgentCompletions(Resource):
    @ns_conf.doc("agent_completions")
    @api_endpoint_metrics("POST", "/agents/agent/completions")
    def post(self, project_name, agent_name):
        """Queries an agent given a list of messages"""
        # Check for required parameters.
        if "messages" not in request.json:
            return http_error(
                HTTPStatus.BAD_REQUEST, "Missing parameter", 'Must provide "messages" parameter in POST body'
            )
        agents_controller = AgentsController()

        try:
            existing_agent = agents_controller.get_agent(agent_name, project_name=project_name)
            if existing_agent is None:
                return http_error(
                    HTTPStatus.NOT_FOUND, "Agent not found", f"Agent with name {agent_name} does not exist"
                )
        except (ValueError, EntityNotExistsError):
            # Project needs to exist.
            return http_error(
                HTTPStatus.NOT_FOUND, "Project not found", f"Project with name {project_name} does not exist"
            )

        # set mode to `retrieval` if agent has a skill of type `retrieval` and mode is not set
        if "mode" not in existing_agent.params and any(
            rel.skill.type == "retrieval" for rel in existing_agent.skills_relationships
        ):
            existing_agent.params["mode"] = "retrieval"

        messages = request.json["messages"]

        completion = agents_controller.get_completion(
            existing_agent,
            messages,
            project_name=project_name,
            # Don't need to include backoffice_db related tools into this endpoint.
            # Underlying handler (e.g. Langchain) will handle default tools like mdb_read, mdb_write, etc.
            tools=[],
        )

        output_col = agents_controller.assistant_column
        model_output = completion.iloc[-1][output_col]
        trace_id = completion.iloc[-1]["trace_id"]

        response = {"message": {"content": model_output, "role": "assistant", "trace_id": trace_id}}

        if existing_agent.params.get("return_context", False):
            context = []
            if "context" in completion.columns:
                try:
                    last_context = completion.iloc[-1]["context"]
                    if last_context:
                        context = json.loads(last_context)
                except (json.JSONDecodeError, IndexError):
                    logger.warning("Error decoding context:", exc_info=True)
                    pass  # Keeping context as an empty list in case of error

            response["message"]["context"] = context

        return response
